The present invention relates to a portable fuel analyzer, and more particularly to a portable analyzer which identifies whether a vehicle fuel sensor is operating properly.
In some flexible fuel vehicles (FFVs) it has been proposed to use a mixed fuel system for a mixed fuel such as a gasoline/alcohol mixture. In this type of vehicle, a measure is employed in which the fuel injection and ignition timing are controlled in accordance with the mixing ratio of the fuel. A fuel sensor within the vehicle fuel tank measures this ratio. Proper operation of the fuel sensor is thus particularly important to the smooth operation of the engine.
The fuel sensor is typically of a capacitance type that includes a pair of spaced electrodes submerged in the fuel. A signal representative of the capacitance established between the positive and negative electrodes under electrostatic charging is transmitted through lead wires to a separate control circuit where subsequent signal conversion and processing are carried out. The dielectric constant of the fuel is detected by measuring the capacitance established between the electrodes and the mixing ratio of the fuel is derived from the dielectric constant.
In many instances, the fuel sensor may be incorrectly identified when vehicle operation is unsatisfactory. This is undesirable as it is time consuming and expensive to replace the vehicle fuel sensor. It is further desirable to identify whether the quality of the fuel may be the cause of unsatisfactory operation. Accordingly, it is desirable to confirm proper operation of the fuel sensor and fuel quality without actually removing the fuel sensor from the vehicle.
The portable fuel analyzer according to the present invention includes a funnel to receive a mixed fuel. The funnel includes one or more input ports such that a mixed fuel sample is directed into a container having a sensor. The sensor is a capacitance type sensor which typically includes a pair of spaced electrode plates submerged in the fuel sample within the container. A display which includes a red and a green LED, communicates with the processor to indicate a quality of the fuel mixture.
In use, an operator extracts a mixed fuel sample from a vehicle fuel tank. The fuel sample is pored into funnel such that the fuel sample is collected in the container. The fuel sample forms the dielectric for the sensor. The dielectric constant of the fuel sample is detected by measuring the capacitance established between the electrode plates and the processor determines the alcohol content of the mixed fuel sample.
The processor illuminates either a Red LED or a Green LED if the measured conductance is above or below a predetermined value. The predetermined values are defined to separate an acceptable fuel sample from an unacceptable sample. An operator is thus immediately identified whether the vehicle fuel is tainted.
The portable fuel analyzer is linked to an evaluation unit to determine a frequency measurement based upon signals from the sensor. The frequency measurement is representative of a percentage of alcohol content in the mixed fuel sample. The evaluation unit is linked to a vehicle undergoing service such that the frequency measured by the vehicle fuel sensor can be determined. The evaluation unit compares the frequency from the vehicle fuel sensor with the frequency from the portable fuel analyzer. The following determinations can thus be defined in a rapid and effective manner without the necessity of removing the vehicle fuel sensor from the vehicle:
If the green LED is illuminated and the portable fuel analyzer indicates a different frequency than the vehicle sensor, the vehicle sensor is defective and should be replaced;
If the green LED is illuminated and the portable fuel analyzer indicates the same frequency as the vehicle sensor, another vehicle component is at fault other than the vehicle sensor;
If the red LED is illuminated, the mixed fuel sample is tainted and a determination about the vehicle sensor cannot be determined.
The present invention therefore provides a portable fuel analyzer that receives a fuel sample from a vehicle to determine whether a vehicle fuel sensor is operating properly without actually removing the fuel sensor from the vehicle.